Conventionally, in the process of manufacture of LSI, optical lithography technology has normally been applied for reproduction of a pattern drawn on a mask. But the optical lithography technology is known to reach its patterning limit up to 0.5 .mu.m and besides, because of effect of Fresnel diffraction and shortness of focal distance, formation of a more compact pattern with less than 1 .mu.m requires introduction of a multi-layer resist and CEL process. On account of such, the process involved becomes complicated and results in a low product yield, which leads to an assessment that such a method will come to end in the near future. Probable replacing new methods are thought to be the direct drawing with electron beam and X-ray lithography. Wherein, the direct drawing with electron beam is defective in throughput, accuracy of stage connection and inevitable introduction of multi-layer resist to attain a height aspect ratio. In contrast, the X-ray lithography is based on image copy or transfer, for which it is advantageous to mass reproduction and it is also based on use of a ray having several angstroms to several tens of angstroms in wavelength, for which the effect of undesirable diffraction may be disregarded in substance and resolution thereby is expected to reach up to 0.1 .mu.m.
The X-ray lithography includes, simply classed, two methods. One is a method that is presently prevailed, proxim method which comprises X-ray exposure in a proximate distance of about 10 .mu.m between a mask and a wafer to transfer a pattern on the mask. Another one is X-ray projection and exposure method which transmits a pattern shadow to a wafer with aid of an X-ray imaging device.